Relationship between Coercivity and Microstructural Changes During DR Treatment in the HDDR‐processed NdFeCoB Alloy

Abstract

Abstract Relationship between coercivity and microstructural changes during desorption‐recombination (DR) treatment in the hydrogenation‐decomposition‐desorption‐recombination (HDDR) processed NdFeCoB alloy has been studied by a combination of different experimental methods. In the early DR stage, coercivity was very small and after a certain period of the DR treatment, the coercivity abruptly increased. The corresponding changes in positron lifetime spectrum, X‐ray diffraction (XRD) spectrum, and thermal desorption spectrum (TDS) were measured. The changes suggest that an Nd‐rich phase formed among recombined Nd 2 (Fe,Co) 14 B grains in the DR treatment plays an important role for the onset of coercivity in the Nd‐Fe‐Co‐B HDDR‐processed alloy. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.